Model Output Discussion - Into 2024

[Ali1977]

Need some good EC ens to settle the ship - then let’s hope the 06gfs jumps back on the big freeze wagon

[That ECM]

[bluearmy]

7 hours ago, RainAllNight said:

Here is some objective data on this subject:

https://charts.ecmwf.int/products/plwww_w_other_ts_upperair?area=Europe&day=5&score=Anomaly correlation

NCEP = GFS, CMC = GEM

 

7 hours ago, Kentspur said:

Does this also suggest Christmas day its only worth checking UKMO model for any idea of the forecast for a few days away look at the very poor performance by all the other models. Assuming the balloon data that gets mentioned every Christmas period. Very intriguing!!

Assuming those are day 5 numbers, it seems that the runs from 20 dec for Xmas day had some v dodgy data in them. And it’s across all models. Tough to check back and see what could have happened. It looks like the 20th was the day that the zonal strat flow turned from its slow progression stronger and began to fall. Don’t suppose there are any cross sectional archived charts from that day or the period approaching to see if there we were any reversals in the flow forecast nearer the pole ?

[cyclonic happiness]

Just now, Lukesluckybunch said:

Brilliant ecm mean..maybe the best yet!

The ECM always lags behind when it comes to downgrading.

I'll leave this malarkey and come back on Monday, if they are still downgrading, I'll save myself the bother and write it off.

I'm sure that 20 years ago, we used to have much more reliable models.....ho hum!   See you Monday, have a good weekend 

[Dennis]

the vortex is heading for a split , pv lobe wil be knocked out in parts 

thats a good sign for the cold patterns 

 

[Catacol]

15th Jan now sneaks into the range of ECM op. 

@Scott Ingham - you are a genius.

[Marting]

ECM ensembles showing colder still as 10 day chart has not scale over 6c on it!

The 15 day charts showing a strong northerly influence on day 15

[bluearmy]

2 minutes ago, Mike Poole said:

But the ECM at T240 is not there yet, so how do you know?

It’s great for UK cold, but that is not a Greenland high - yet.

It was a comment aimed at those who have been consistently predicting the spell would fail regardless, to be clear.

How do we define a Greenland high Mike ?

does it have to full on greens/yellows covering the whole country?  I’d say that day 10 ec is a decent Greenland height rise centred s Greenland 

I would have thought that a sustained block there would suffice for us in any case - even if that means the n and nw of Greenland isn’t covered by a full upper ridge ? (Which might help with fears of west based?) 

[That ECM]

Just now, Catacol said:

15th Jan now sneaks into the range of ECM op. 

@Scott Ingham - you are a genius.

Going to need a pic of him making a snow angel if it lands for sure.

[ItNeverSnowsInWindsor]

6 minutes ago, That ECM said:

That is impressive!

[MJB]

24 minutes ago, Drifter said:

I know some think it’s a myth, but the Meto text updates often seem to lag the models by 24hrs. 

That might be the case but they won't base their updates on GFS, they have their own super computers which we don't see.

[Mike Poole]

In my opinion, the best tool to look at when things get a bit hairy in the medium term is the clusters.  What are the options the models are seeing?

T120-T168:

I think the difference here between the two is that cluster 2 is quicker to lower heights in the vicinity of the UK.  But in doing that a small low appears east of Greenland which might prove problematic later in getting a clean evolution.

T192-T240:

Clusters 1 and 3 look excellent for the UK in terms of the cold progression, maybe a suggestion on cluster 1 that the high could leak to the Canadian side, which may alter things down the line.  Cluster 2 the high is less well oriented and the cold is held back a little.

T264+:

Cluster 1 rock solid.  Cluster 2 good until day 13.  Cluster 3 (this is the one with the leaking high) and the high sinks.  I think this timeframe is an upgrade on yesterday, when there was more uncertainty.  

 

[bluearmy]

Eps aren’t seeing a breakdown of the sort most on here are fearing 

at worst a mid lat high drifting in end week 2 seems to be the alternative to cyclonic cold 

[frosty ground]

3 minutes ago, bluearmy said:

How do we define a Greenland high Mike ?

does it have to full on greens/yellows covering the whole country?  I’d say that day 10 ec is a decent Greenland height rise centred s Greenland 

I would have thought that a sustained block there would suffice for us in any case - even if that means the n and nw of Greenland isn’t covered by a full upper ridge ? (Which might help with fears of west based?) 

We call it a glorified Atlantic ridge, energy is still crossing northern Greenland hence the low forming on the north east of the high and looks to move south a bit like the GFS 18z yesterday,

 

the wobbly wheel has now struck the ECM op and the GFS has lost some bolts

[SollyOlly]

38 minutes ago, Chesil View said:

Its not really that hard to remain positive when the top two verifying models are steady as a rock and the one that always goes a bit awol on when it comes to cold is doing its usual wobble. 

Totally agree, I am cautious by nature but surely we'd all rather have UKMO and ECM on board and a (minor) GFS wobble than the other way round...

[Liam Burge]

30 minutes ago, Drifter said:

I know some think it’s a myth, but the Meto text updates often seem to lag the models by 24hrs. 

Because the professionals at MetO don't throw their toys out the pram over a few model runs (that are literally complete outliers). The cold is definitely still on, and I believe GFS 6z will be back on track.

[Dennis]

its near a split allready.... it seems no succeeding now 

later midmonth try again i think

[sheikhy]

That is some ecm mean!!!!!

[January Snowstorm]

2 minutes ago, bluearmy said:

Eps aren’t seeing a breakdown of the sort most on here are fearing 

at worst a mid lat high drifting in end week 2 seems to be the alternative to cyclonic cold 

Indeed but most on here look for cold in the hoped that it delivers snow eventually. I can only speak for myself but if it's not going to snow I have zero interest in cold

We are waiting a long-time to get this home. A mid latitude high eating into January is not what most want. It might as well get mild 

Edited January 5 by January Snowstorm

[mountain shadow]

16 minutes ago, Mike Poole said:

But the ECM at T240 is not there yet, so how do you know?

It’s great for UK cold, but that is not a Greenland high - yet.

It was a comment aimed at those who have been consistently predicting the spell would fail regardless, to be clear.

It looks like a Greenie blocking high to me, ok, the core of the heights aren't over the plateau but Greenland is a big place.

 

[MJB]

10 minutes ago, bluearmy said:

How do we define a Greenland high Mike ?

does it have to full on greens/yellows covering the whole country?  I’d say that day 10 ec is a decent Greenland height rise centred s Greenland 

I would have thought that a sustained block there would suffice for us in any case - even if that means the n and nw of Greenland isn’t covered by a full upper ridge ? (Which might help with fears of west based?) 

So is the GH the inner marking or the outer marking? When I looked at chart I took the GH to be the outer marking....................Thoughts?

[IDO]

Looking at the Arctic high is an important part of the puzzle, and we can see why the models are having a rethink. Compare ECM D8 -v- D7, yesterday and today's 0z:

The Arctic High blended with the Greenland Heights yesterday, acting as an anchor and feed for stable Greenland Heights. This morning, the Arctic wedge merges mainly with the Pac ridge. D10 ECM manages to get a slither of a wedge to link between the Pac Ridge and GH to pull the heights north, but will that be there on the 12z?

I am watching this to see if the impact of losing the Arctic residue wedge to the Pacific ridge will be a trigger for a less stable GH. It may be moot, but I would be happier for Arctic Heights to blend with the Greenland block.

Edited January 5 by IDO

[SLEETY]

Don't just rely on the op run people are told, but they still do it,time after time, then call downgrade at chartt over 10 days away and ignore the excellent earlier part of the gfs in this case 

SAME every winter. 

 

 

[Mike Poole]

9 minutes ago, bluearmy said:

How do we define a Greenland high Mike ?

does it have to full on greens/yellows covering the whole country?  I’d say that day 10 ec is a decent Greenland height rise centred s Greenland 

I would have thought that a sustained block there would suffice for us in any case - even if that means the n and nw of Greenland isn’t covered by a full upper ridge ? (Which might help with fears of west based?) 

Good question, I would define it by heights not sea-level pressure, for a start, as discussed yesterday.  At day 10, the heights are highest just south of the tip of Greenland on the ECM, which is not quite there (yet) when we were seeing it over the country (at some time, not necessarily T240) on the previous runs.

Fully agree that a high centred where the ECM has it T240 might work out just fine for the UK.

[Captain Shortwave]

1 minute ago, mountain shadow said:

It looks like a Greenie blocking high to me, ok, the core of the heights aren't over the plateau but Greenland is a big place.

 

The more encouraging element is that is even if the Greenland high doesn’t come off, the failure looks like being a lack of amplitude and instead we end up with a persistent Atlantic ridge, which of course will deliver cold from the north regardless and offer other routes beyond. What we don’t want is the cut off high racing westwards and the Atlantic lows racing back towards the UK, that doesn’t look likely at this time.